The Trompowski Attack is a chess opening starting with the moves 1.d4 Nf6 2.Bg5. It is named after the one-time Brazilian champion Octavio Siqueiro F. Trompowski (1897–1984) who played it in the 1930s and 1940s.

With the second move, White is intending to exchange his bishop for Black´s knight inflicting doubled pawns upon Black in the process. This is not a lethal threat, Black can choose to fall in with White´s plan. (See Main lines).

Black has a number of ways to meet the Trompowski, some avoid doubled pawns while others allow them. The most common Black responses are discussed here.

2...Ne4 is the most common response. Although Black violates an opening priciple ("Don´t move the same piece twice in the opening"), Black´s move attacks White´s bishop, forcing it to either move again or be defended.

3.h4 defends the bishop, and Black should avoid 3...Nxg5? since that will open up a file for the White rook. Instead Black can start making a grab for the centre and kick the White bishop away with a timely ...h6 advance.

Usually, White retreats with 3.Bf4 or 3.Bh4. In this case, Black will try to maintain his knight on e4, or at least get a concession before retreating it. For instance, if White chases the knight away with f3, he will have taken away the best development square from his own knight.

2...e6 also avoids doubled pawns since the knight is now defended by the queen. Also 2...e6 opens up for the Black king´s bishop to be developed. On the debit side, the knight is now pinned, and this can be slightly annoying.

2...d5 makes a grab for the centre, allowing White to inflict the doubled pawns on Black. If White does so, Black will try to show that his pair of bishops is valuable, and that White has wasted time by moving his bishop twice in order to trade it off.

2...c5 also makes a grab for the centre, planning to trade off the c-pawn for White´s d-pawn. Again, White can inflict doubled pawns, and again Black will try to make use of his bishop pair.

2...g6 is another line allowing White to inflict the doubled pawns. Black´s development is slightly slower than in the two lines mentioned above. Black is intending to fianchetto his dark-squared bishop which is unopposed by a White counterpart, and will try to prove that this is more important than the doubled pawn weakness.